This invention relates to sport hot air balloons, and more particularly, to a deflation panel and maneuvering vent for the balloon and to a closure for closing and controlling the opening of the deflation panel.
Hot air balloons generally include a balloon envelope having a circular top opening, a gondola suspended from the bottom of the envelope, and a top cap for closing the top opening. During normal flight, the top opening is closed, but it is opened at the end of the flight to rapidly deflate the balloon. The deflation portion of the opening is sometimes referred to as the "deflation panel". The device to close the opening must be exceedingly reliable so as to only release air when desired. Furthermore, the device should be easy to use, easy to reinstall, require relatively little maintenance and be fail-safe if possible. Most balloons also include a second opening, called a maneuvering vent, to release controlled amounts of hot air to effect the vertical speed of the balloon. These vents, which may be opened and closed many times in flight, must also be easy to operate, allow quick reaction and be fail-safe.
In one of the earliest deflation panel designs, the top of the balloon was extended into a chimney-like structure. In normal operation, a large cylinder of material was gathered together and secured with a cord to hold the chimney closed and retain the air. To release the air the cord is released allowing the chimney to open, thereby emptying the balloon. This system is fairly secure in keeping the balloon closed but is far less reliable in opening upon command and was not considered to be fail-safe.
At present, the most widely used deflation panel is referred to as the "circular rip" in which a large circular panel is secured to a similarly sized opening in the top of the balloon. The panel is fastened to the balloon with a hook and loop fastener such as Velcro. This system is highly reliable in retaining and releasing air when desired. Its largest drawback is the time-consuming reinstallation process and a maintenance requirement which is more expensive than others.
The second most common deflation panel is known as a parachute top which is a circular panel filling a circular orifice in the balloon. The panel is not attached directly to the balloon but is retained in place by radial cords which extend from the panel to anchor points on the balloon envelope's surface. This serves not only as a deflation panel but also as a valve to release controlled amounts of air for maneuvering purposes. The parachute top is reliable in retaining air but is deficient in its ability to release air when needed. Furthermore, installation is easy but dimensional changes such as shrinkage can alter the fit resulting in leakage, which then necessitates maintenance. Furthermore, the combination of deflation and maneuvering is an advantage but is also a problem in that separation of those two functions is necessary to allow for redundancy of control as a safety factor. Reference is made to U.S. Pat. No. 2,404,659, dated July 23, 1946, which discloses a parachute-style top; U.S. Pat. No. 3,131,889 that discloses a deflation mechanism; and U.S. Pat. No. 3,229,932, which discloses a maneuvering port.
It is an object of this invention to provide a closure system for use in a sport hot air balloon which avoids the problems of the prior art.
Another object of this invention is to provide a closure system which is highly reliable and does not require time-consuming reinstallation or high maintenance.
It is another object of this invention to provide a system which provides for both deflation and maneuvering, in which these functions are separate and which allows for redundancy between the two functions.
These and other objects of this invention will become apparent from the following description and appended claims.